Thermostatic accelerating pump control



2 SHEETS--SHEET 1 F IG. 3.

INVENTOR.

ATTORNEY L. D. BOYCE Jan. 13, 1953 THERMOSTATIC ACCELERATING PUMP CONTROL Filed Jan. 10, 1950 LEONARD D. BOYCE F IG. 2.

Jan. 13, 1953 L. D. BOYCE THERMOSTATIC ACCELERATING PUMP CONTROL 2 SHEETS-SHEET 2 Filed Jan. 10,1950

1 w x I miriii INVENTOR. LEONARD D. BOYCE %%W,

ATTORNEY Patented Jan. 13, 1953 'TITERMQ'STATIC ACCELERATING PUMP CONTROL Leonard D. Boyce, Kirkwood, Mo assign'or to Garter Garburetor Company,- St. Louis, Mo -a.

corporation of Delaware nppiicat'icniianuary 10, 1950,- 'seriallfiio. 113731 1 1 7 1D Glaims. 1

This invention relates to earburet'ors for-internal combustion engines, an'd' co'nsists particularly in a novel control for accelerating pumps therefor.

Accelerating pumps for carburetors are generally operatively connected to the throttle s'haft so that as the throttle is opened the pump discharges a fixed amount 'of fuelinto the mixture conduit, the amount of fueldischar'ge'd depending upon the capacity of the pump, length or stroke, and amount of throttle movement. Although the requirements for an accelerating charge diminish as the ambient temperature increases, a conventional pump discharges as much fuel when it is warm as when it is cold.

Accordingly, an object of this invention is to provide an accelerating pump in which the amount of fuel discharged diminishes in proportion to increases in the ambient temperature. I achieve this object by providing thermostatic means for shortening "the pum stroke as the ambient temperature increases.

Additional objects and advantages will appear in the specification when read in connection with the accompanying drawings, in which:

Fig. '1 is a plan view of acarburetorincor orating my invention;

Fig. 2 is a partial vertical section cf the 'carburetor of Fig. 1 along th'eline 22;

Fig. 3 is a fragmentary bottomyi'ew of the same carburetor;

Fig. 4 is a vertical section view along the line 4-4 of Fig. 1;

Fig. -5 is a fragmentary vertical section view similar to Fig. 4, but showing the pump piston limited to a shortened stro'ke.

Referring now to the drawings, a downdraft carburetor is generally indicated at 10. Carburetor It! has a mixture conduit 1 1.,fianged at its lower end as at 13 .for attachment to the intake manifold of an internal combustion engine, and a float controlled constant level fuel reservoir 15. Fuel for operation is provided to mixture conduit H through orifice l6, and passage ll, extending from reservoir 15 into the central part of web [9 bisecti-ng mixture conduit ll. tional fuel, for operation at lower manifold suction is admitted topassage H through valve 2i! and passage 21; valveZl] tbeing urged-downward, toward closed position by ipiston 22, which is drawn downwardlyin cylinder 24 ?by suction, and urged upwardly by calibratedc'oill'spring 23. The outlet of mixture conduit -'H is controlled by throttle valve 21, mounted on shaft 28 which is rotatably journalled in the mixture conduit wall structure.

Addi- Fuel for idling is provided through restricted tube 29, associated passages (not shown) passage 30 and idle ports 3.! discharging into the mixture conduit "adjacent throttle 21.

Additional fuel for acceleration is provided by an accelerating pump consisting of cylinder 33 formed in the wall of reservoir 85, inlet check valve 35"c'ommunicating'with reservoir l5 through passage 36, an outlet passage 38 leading to mixture conduit H for discharge thereinto, and piston 39 slidably mounted in cylinder 33. Piston 39 is formed with a stem 4i, around which is mounted coil spring 42,, the lower end of which bears against plunger 39 and the upper end of which is seated in cup 44 which is slidably mounted on stem 41. Cup 44 abuts against shoulder 45, so that spring 42 urges plunger 39 downwardly in cylinder 33.

Stem M is formed with two sets of horizontal downwardly facing shoulders 58, at the stems upper extremity, and 5| at a somewhat lower position on the stem. Their function will be described in detail below.

For elevating plunger 33, a link 52 having a horizontally extending upper end portion 53 is slidably mounted in vertical guideway 54 formed in the reservoir wall structure and extending above the normal fuel level therein. Stem 4| passes through a horizontal slot in end portion 53 "of link 52 so that shoulders iii) are urged downwardly against the upper surface of end portion '53 of link 52, thereby forming a one- Way, operative connection between link 52 and stem '41. At its lower end link 52 is adjustably connected by short link 53 :to arm 5-! rigid with throttleshaft 28,:so that asthrottle 21 .is moved toward open position, 1ink52 is moved downwardly, thereby permitting spring 42 to force plunger 39 downwardly to discharge .fuel from pump cylinder 33. Closing-movements of throttle 21 cause link 52 to move upwardly so as to raise plunger 39 andthereby draw a quantity of fuel into cylinder 33 from reservoir [5.

For varying the length of stroke of plunger 39, a device is provided consisting of vertical shaft 58 rotatab'ly .journalled in the reservoir wall structure at B0, and having-rigidly secured to its upper end a horizontal arm 6|. The lower end of shaft-I 58 extends below the bottomof the fuel reservoirandisbent at a right angle to form a radial arm 53a having at its outer extremity a slotted cylindrical opening 66. The inner end portion of a helical bimetal thermostat 6 5 fits in slot 63 in rigidgpost-fii and its outerLhQoked in arm .SBa o f shaft 58, so that :as engine temperature changes, the outer end of thermostat 65 rotates arm 58a and vertical shaft 58. Arm 6] is formed with a vertical channel at its outer end, the width of the channel being equal to the width of the narrowest portion of stem 4|, so that the upper surfaces 69, Ill, and 1!, respectively, of stepped flanges 12 may engage the lower surfaces of shoulders 5| to prevent further downward movement of stem 4! and plunger 39.

When the engine is cold thermostat 65 positions arm Bi so that lowermost steps 69 of flanges 12 are interposed beneath shoulders 5|, thus permitting plunger 39 to move its maximum discharge stroke; as the engine temperature increases, medium steps and uppermost steps H are successively interposed beneath shoulders 5i, 7

thereby reducing the discharge stroke length and consequently the quantity of fuel discharged in proportion to engine temperature.

The invention may be modified in various respects as will occur to those skilled in the art and the exclusive use of all modifications as come within the scope of the appended claims is contemplated.

I claim:

1. In a pump comprising a cylinder and a piston slidably mounted therein, a shouldered stem attached to said piston for imparting axial movement thereto, stepped stop means arranged for variable positioning in the line of movement of said shouldered stem, and thermal responsive means comprising a thermostat operatively connected to said stop means for successively positioning the stepped portions in the line of movement of said shouldered stem.

2. In a pump comprising a cylinder and a piston slidable therein, a shouldered stem attached to said piston for imparting axial movement thereto, a stepped stop member rotatably journalled for variable positioning in the line of movement of said shouldered stem, and thermal responsive means comprising a thermostat operatively connected to said stop member for successively rotating the stepped portions into the line of movement of said shouldered stem.

3. In a pump comprising a cylinder and a piston slidable therein, a shouldered stem attached to said piston for imparting axial movement thereto, a stepped stop member journalled for rotation in a plane normal to the axis of said cylinder and adapted to engage said shouldered stem for varying the axial movement of said piston, and thermal responsive means comprising a thermostat operatively connected to said stop member for successively rotating the stepped portions thereof into the line of movement of said shouldered stem.

4. In a pump comprising a cylinder having inlet and outlet valves, a piston slidable within said cylinder, a shouldered stem attached to said piston for imparting axial intake movement thereto, spring means for imparting discharge movement to said piston, a stop member for limiting the stroke of said piston, said stop member comprising a channel substantially of equal width with the narrow portion of said shouldered stem, the flanges of said channel being formed with a series of steps adapted to abut against the shoulders of said stem for limiting the movement of said stem and piston.

5. In a pump comprising a cylinder having inlet and outlet valves, a piston slidable within said cylinder, a shouldered stem attached to said piston for imparting axial intake movement thereto, spring means for imparting discharge movement to said piston, a stop member for limiting the stroke of said piston, said stop member comprising an arm pivoted at one end and having at its outer end a channel element substantially of equal width with the narrow portion of said shouldered stem, the flanges of said channel element being formed with a series of steps adapted to abut separately against the shoulders of said stem for limiting the movement of said stem and piston, and thermal responsive means for rotating said stop member.

6. In a pump comprising a cylinder having inlet and outlet valves, a piston slidable within said cylinder, a shouldered stem attached to said piston for imparting axial movement thereto, a moveable stop member for limiting the stroke of said piston, said stop member comprising a channel having its flanges spaced to straddle the narrow portion of said stem, said flanges of said channel being formed with a series of steps adapted to abut against the shoulders upon movement of said stem for limiting the movement of said stem and piston, and thermal responsive means for moving said stop member to position the steps of said shoulders into position for engagement with the shoulder of the stem in accordance with temperature conditions.

'7. In a pump comprising a cylinder having inlet and outlet means, a piston slidable within said cylinder, a shouldered stem attached to said piston for imparting axial intake movement thereto, a stop member for limiting the stroke of said piston, said stop member consisting of a rotatable arm journalled at one end and having at its outer end a series of steps arranged parallel to the longitudinal axis of said pump for separate engagement with said shouldered stem, and thermal responsive means associated with said arm for moving said steps successively into position for engagement with said shouldered stem.

8. In a carburetor having a mixture conduit, 2. throttle valve therein, and a constant level fuel reservoir, an accelerating pump comprising a cylinder formed in the wall of said reservoir, inlet and outlet means connecting said cylinder respectively with said reservoir and said mixture conduit, a piston slidable in said cylinder, a shouldered stem attached to said piston, an operative connection between said stem and said throttle valve, a stepped stop member arranged for varia- -ble positioning in the line of movement of said shouldered stem, a rotatable arm supporting said stepped stop member, a shaft rigidly secured to said rotatable arm, said shaft being journalled in a portion of the wall structure of said reservoir extending above the fuel level therein and extending outwardly through the bottom wall of said reservoir, a thermostat secured at one end to the lower extremity of said shaft and fixed at its other end wtih respect to the bottom wall of said reservoir.

9. In a pump comprising a cylinder and a piston slidably mounted therein, operating means for the piston including a stem, said stem being formed with a downwardly facing shoulder, a stop member formed with a plurality of upwardly facing spaced wall portions arranged for movement into the line of movement of the downwardly facing shoulder, and a thermal responsive means including a thermostat operatively connected to said stop member for successively positioning the upwardly facing spaced wall portions in the line of movement of said downwardly facing shoulder.

10. In a pump comprising a fluid chamber hav- REFERENCE S CIT ED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Becker 'Ap'r. 26, 1892 Hctchkiss Nov': 10, 1914 Davis Mari 20, 1923 Neuls Feb. 22, 1927 Newton Dec: 18, 1928 Parsons May 9, 1933 Chandler Nov. 14, 1933 Douglas Sept. 18, 1934 Boyce July 28, 1936 Fee Oct. 4, 1938 Ball Aug. 25, 1942 Weber May 7, 1946 

